"We understand that the sides have no intention of developing their offensive strategic capabilities against each other," said Ryabkov.

"But we need safeguards that this is how things will remain in the future."

President Dmitry Medvedev stepped up the diplomatic pressure over the weekend by telling NATO heads of states in a letter that a European missile defence system could only be viable if Russia took part.

He and US President Barack Obama are set to meet on the sidelines of a Group of Eight leading industrialised nations' summit in France at the end of the month.